Dominant Eye Test
At some point, you may have heard the terms "dominant eye" or "ocular dominance," but what exactly do they mean, and how can you determine your dominant eye? Since we usually use both eyes at once, having a dominant eye is often an overlooked trait. Below are some basics on how to find your dominant eye and when eye dominance can make a difference.
How to tell which eye is dominant
A dominant eye doesn't mean better vision but rather guiding the other better because of preference. Your dominant eye provides slightly more input to the visual cortex of your brain and relays the information more accurately, especially object location. The visual cortex is the brain region that receives and processes information from the retina.
Eye dominance can vary from person to person. While someone may have a strong degree of dominance in one eye, another may have an eye with a lesser difference in dominance. For most people, eye dominance won't impact day-to-day living and is more of a curiosity.
The eye dominance test
If you're curious, there are several techniques to determine your dominant eye. Below are two basic tests, called "sighting tests," which can be done quickly and easily.
For the first test:
- Extend your arms in front of you, with your palms facing away from you, bring your hands together, crossing your thumbs and forefingers to form a small triangular opening.
- With both eyes open, choose a small object in the distance (about 15-20 feet away) and centre this object as you look through the small opening.
- Close one eye at a time. When you close one eye, the object will be stationary. When you close the other eye, the object should disappear from the triangle or jump to one side.
If the object does not move as you look through with one eye, that is your dominant eye. For example, if you look through the opening at the object with your right eye open and left eye closed and the object is still centred, you are right-eye dominant.
For the second test:
- Extend one arm in front of you with your thumb or index finger on that hand in an upright position.
- With both eyes open, focus on an object in the distance.
- Move your arm so that you superimpose your thumb on that object (it is normal if your thumb partially disappears).
- Alternate closing one eye at a time.
The eye that keeps your thumb directly in front of the focused object while the other eye is closed is your dominant eye.
If you still can't tell, ask your eye doctor at your next eye exam. Some studies have shown that sighting tests, though generally accurate, can be affected by handedness and other non-visual factors. They argue that non-sighting tests are more precise in determining eye dominance. In these tests, both eyes are kept open and visual stimuli are presented to each eye separately using special optical devices. These tests can only be performed in specialized vision clinics or research facilities.
Eye dominance and handedness
While eye dominance and handedness are not directly related, they may be associated, but it is impossible to predict eye dominance based on handedness alone. Studies suggest that most of the global population is right-handed, but only a third have a dominant right eye. Research has shown that the odds of a right-handed person being right-eye dominant are high, approximately 2.5 times greater than the odds of that person being left-eye dominant.
Is it possible to not have a dominant eye?
Most people have a dominant eye, but there are rare cases when neither eye is dominant. Some people have mixed or alternating ocular dominance, meaning one eye is dominant for certain tasks while the other is preferred for different functions. There is a spectrum of degree when it comes to eye dominance. Some people may have a significant difference between their eyes, while others may have a minimal difference.
Dominant eye in sports, shooting and photography
You may notice your dominant or preferred eye when you use a camera, microscope, or telescope. Understanding which is your dominant eye can improve your performance in certain sports and activities, especially any that require accurate aim. Minor adjustments to the position of your head or hands can help put your dominant eye in a better spot, allowing you to level up during leisure time or competitions.
In some sports, taking full advantage of your dominant eye is fundamental and requires positioning your head in a way that allows you to do so. Golf and baseball are two examples in which this is necessary. In golf, certain strokes must be perfectly aligned and require turning your head fully to use and benefit from your dominant eye. While batting in baseball, your head must be turned enough for your dominant eye to see the pitch's rotation, position and speed.
Some people experience crossed dominance, where their dominant eye and hand are not on the same side. This can cause problems during shooting, but being aware of this can help you make adjustments to improve accuracy. To shoot and hit moving targets, you should aim with your dominant eye; if you use your non-dominant eye, your target won't be in the right place. If possible, shooting with the hand that matches your dominant eye is recommended. Another way to compensate for cross-dominance is to keep both eyes open until right before you take your shot. You can use 100% of your peripheral vision and depth perception with both eyes open.
Knowing your dominant eye can also aid in taking better photos. When looking through the viewfinder of a camera with your dominant eye, you will get a more accurate preview and alignment of the shot. If you're using your non-dominant eye, you may notice that specific details will end up displaced or outside the frame in the final image.
Eye dominance problems
For the vast majority, eye dominance has no bearing on day-to-day living. Generally, the term dominant eye is used to describe the preferred eye in typical visual conditions where both eyes function well as a team. In some cases, dominant eye is used to refer to the normal functioning eye in cases of strabismus or amblyopia.
While not the only cause, a strong dominant eye can sometimes trigger amblyopia or lazy eye. As one eye relays stronger visual signals than the other, it causes the non-dominant eye to become weaker over time. This can be treated early by patching the dominant eye in hopes of strengthening the non-dominant one. There are also eye exercises that can be done to help improve vision.
Your dominant eye shouldn't be an obstacle on a daily basis. It's beneficial to be aware of this as it can help in certain activities, but as long as your vision is aligned and clear, it shouldn't matter which eye is dominant. Whether to improve performance or out of curiosity, try our easy at-home tests to discover your dominant eye. If you have any questions or concerns about your dominant or non-dominant eye, visit our Optical Centre and speak to one of our opticians online today.